<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- 开发环境版本，包含了有帮助的命令行警告 -->
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <button v-on:click="min">-</button>
       
        <input  v-model="message" >
        <button v-on:click="add">+</button>

        <button v-on:click="min">-</button>
       
            <input  v-model="message2" >
        <button v-on:click="add">+</button>
    </div>
    <script>
        var app = new Vue({
            el: '#app',
            data: {
                message: 0,
                message:0
            },
            methods: {
              min:function(){
                  debugger
                this.message = --this.message
             
              },
              add:function(){
                this.message = ++this.message
              }
            }
        })
    </script>
</body>

</html>